[Zelandakh]

appelflapj, on 2017-March-02, 09:00, said:

p opens a weak 12 - 14 no trump and the opps are silent.
you transfer to spades , partner accepts, and you bid 3 hearts promising 5 spades and 4 hearts and a gf hand.

If this sequence shows a 5-4 hand, what would 1NT - 2♣; 2♦ - 3M have shown? I think you should perhaps explain how your NT system works before anyone can really give good advice here, notwithstanding that some have already tried. For the majority of players using transfers, the sequence you used already shows a 5-5 hand of some strength. it is not impossible to use a transfer and new suit this way but if you do then you typically have to match that with an alternative gadget for the 5-5 majors GF hand, such as 1NT - 2♣; 2♦ - 3♦. That, of course, has other knock-on effects. NT systems tend to hand together in a tight dance so you just have to know how your method handles a 5-5 majors GF hand. It does not matter so much what that is so much as that it exists.

As for what to bid over 3♠, again that is highly system dependent. Some will play Serious 3NT here, others Frivolous 3NT and others neither of these. As you can see from the replies, some play 4♥ here as natural and for others it is a control bid of some sort; Nige seems to play it 2-way, which is to my mind almost unworkable. To write that "4♥ has to be a mild slam try" is, quite frankly, ridiculous as well as misleading.

Finally, here is a popular ladder for 5-5 major hands over a 1NT opening in North America:

weak: 2♣, then 2♥ if partner rebids 2♦
INV: 2♦, then 2♠ over 2♥
GF: 2♥, then 3♥ over 2♠

I personally play something completely different to this but the above is probably the easiest stand-by if playing with a pick-up partner or just wanting a basic system for general play.